I don't expect any modder to try this b/c I'm betting this could take some work, I'd guess…but what the heck! I'll ask anyways. {shrug}

If someone captured the final gameplay (in-game engine) w/ it working properly and made that capture a video file (like say the same file format as the Russobit intro video)….
…could it be modded to actually be played at the end-game instead of the final in-game engine)?
Or maybe give at the end the option to have the game render the in-game cut-scene or the captured video of the ending?